Vermont State Police and federal law enforcement officers here were in a state of “heightened awareness and readiness” Friday as a massive manhunt for a suspect in the Boston Marathon bombings unfolded in that city.

A few minutes later, Vermont State Police posted on its Facebook page: “Great work, Boston!”

But earlier Friday, it was unknown where Tsarnaev might be after he fled an engagement with police in which his brother, the other bombing suspect, was killed.

There was no reason to believe that Dzhokhar Tsarnaev was on his way to Vermont, according to Public Safety Commissioner Keith Flynn, but police here adopted a stance of “operational awareness” Friday as a precaution.

“Certainly we monitored the situation in Boston and were ready if needed,” he said. Part of that readiness included being prepared to send assets, including the state police tactical support unit and its armored car to Boston if needed.

Earlier in the day, Flynn said Vermont extended an offer of help and resources to that beleaguered city.

“We let them know we have assets here and we would certainly deploy them if needed,” he said. “There is no routine for what Boston is experiencing right now,” Flynn added. “For that reason, we knew we had to be ready.”

The state police bomb disposal team was kept on readiness status all day Friday, Flynn said, but its members — who are dispersed throughout the state — were not ordered to gather in one place.

While authorities in Vermont emphasized there was no information to suggest that Tsarnaev was trying to come to the state, an incident early in the day involving a Boston cab on Interstate 89 highlighted the level of concern in the state.

“We got a call from a motorist traveling north on I-89 in the Sharon area who reported seeing a Boston cab traveling 40 to 45 mph in the passing lane and, given what’s going on right now (in Boston), they called it in,” said Capt. Glenn Hall of the state police in Williston.

“We came in contact with that cab up in the Williston area,” he said. “We spoke with the driver and there is no indication of any connection” to the Boston manhunt.

The cab had apparently picked up a fare at Logan International Airport in Boston and drove to the Burlington area, police said. The cabbie was returning south on I-89 when police pulled him over shortly before 8 a.m. Friday.

After a short conversation with police, he was allowed to continue on his way.

“We hadn’t gotten any information beforehand to be on the lookout for anything (like a cab), but obviously with what is going on we are vigilant,” Hall said.

Special Agent Paul Holstein, spokesman for the FBI in Albany, N.Y., said Friday that federal authorities in the region were also on alert.

“We’re absolutely aware that within our area of responsibility, including Vermont, there’s a need for great vigilance at this time,” he said. “As far as the specifics of what we’re doing, it’s our policy not to comment on the situation.”

To the east, New Hampshire State Police on Friday deployed a SWAT team and its explosives ordinance disposal unit to support operations in Watertown, Mass., where police focused their search for most of the day.

North of the border, Canadian officials said they, too, were on heightened alert. Dominique McNeely, a spokesman for the Canada Border Services Agency, said Canadian officials were working closely with their U.S. counterparts.

Shelbe Bentson-Fuller, a spokeswoman for U.S. Customs and Border Protection in northern New England, referred questions about any heightened border security to the Department of Homeland Security in Washington.